linux/drivers/macintosh/windfarm_lm75_sensor.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Windfarm PowerMac thermal control. LM75 sensor
   4 *
   5 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
   6 *                    <benh@kernel.crashing.org>
   7 */
   8
   9#include <linux/types.h>
  10#include <linux/errno.h>
  11#include <linux/kernel.h>
  12#include <linux/delay.h>
  13#include <linux/slab.h>
  14#include <linux/init.h>
  15#include <linux/wait.h>
  16#include <linux/i2c.h>
  17#include <linux/of_device.h>
  18#include <asm/prom.h>
  19#include <asm/machdep.h>
  20#include <asm/io.h>
  21#include <asm/sections.h>
  22#include <asm/pmac_low_i2c.h>
  23
  24#include "windfarm.h"
  25
  26#define VERSION "1.0"
  27
  28#undef DEBUG
  29
  30#ifdef DEBUG
  31#define DBG(args...)    printk(args)
  32#else
  33#define DBG(args...)    do { } while(0)
  34#endif
  35
  36struct wf_lm75_sensor {
  37        int                     ds1775 : 1;
  38        int                     inited : 1;
  39        struct i2c_client       *i2c;
  40        struct wf_sensor        sens;
  41};
  42#define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
  43
  44static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
  45{
  46        struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  47        s32 data;
  48
  49        if (lm->i2c == NULL)
  50                return -ENODEV;
  51
  52        /* Init chip if necessary */
  53        if (!lm->inited) {
  54                u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);
  55
  56                DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
  57                    sr->name, cfg);
  58
  59                /* clear shutdown bit, keep other settings as left by
  60                 * the firmware for now
  61                 */
  62                cfg_new = cfg & ~0x01;
  63                i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
  64                lm->inited = 1;
  65
  66                /* If we just powered it up, let's wait 200 ms */
  67                msleep(200);
  68        }
  69
  70        /* Read temperature register */
  71        data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
  72        data <<= 8;
  73        *value = data;
  74
  75        return 0;
  76}
  77
  78static void wf_lm75_release(struct wf_sensor *sr)
  79{
  80        struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  81
  82        kfree(lm);
  83}
  84
  85static const struct wf_sensor_ops wf_lm75_ops = {
  86        .get_value      = wf_lm75_get,
  87        .release        = wf_lm75_release,
  88        .owner          = THIS_MODULE,
  89};
  90
  91static int wf_lm75_probe(struct i2c_client *client,
  92                         const struct i2c_device_id *id)
  93{       
  94        struct wf_lm75_sensor *lm;
  95        int rc, ds1775;
  96        const char *name, *loc;
  97
  98        if (id)
  99                ds1775 = id->driver_data;
 100        else
 101                ds1775 = !!of_device_get_match_data(&client->dev);
 102
 103        DBG("wf_lm75: creating  %s device at address 0x%02x\n",
 104            ds1775 ? "ds1775" : "lm75", client->addr);
 105
 106        loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
 107        if (!loc) {
 108                dev_warn(&client->dev, "Missing hwsensor-location property!\n");
 109                return -ENXIO;
 110        }
 111
 112        /* Usual rant about sensor names not beeing very consistent in
 113         * the device-tree, oh well ...
 114         * Add more entries below as you deal with more setups
 115         */
 116        if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
 117                name = "hd-temp";
 118        else if (!strcmp(loc, "Incoming Air Temp"))
 119                name = "incoming-air-temp";
 120        else if (!strcmp(loc, "ODD Temp"))
 121                name = "optical-drive-temp";
 122        else if (!strcmp(loc, "HD Temp"))
 123                name = "hard-drive-temp";
 124        else if (!strcmp(loc, "PCI SLOTS"))
 125                name = "slots-temp";
 126        else if (!strcmp(loc, "CPU A INLET"))
 127                name = "cpu-inlet-temp-0";
 128        else if (!strcmp(loc, "CPU B INLET"))
 129                name = "cpu-inlet-temp-1";
 130        else
 131                return -ENXIO;
 132        
 133
 134        lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
 135        if (lm == NULL)
 136                return -ENODEV;
 137
 138        lm->inited = 0;
 139        lm->ds1775 = ds1775;
 140        lm->i2c = client;
 141        lm->sens.name = name;
 142        lm->sens.ops = &wf_lm75_ops;
 143        i2c_set_clientdata(client, lm);
 144
 145        rc = wf_register_sensor(&lm->sens);
 146        if (rc)
 147                kfree(lm);
 148        return rc;
 149}
 150
 151static int wf_lm75_remove(struct i2c_client *client)
 152{
 153        struct wf_lm75_sensor *lm = i2c_get_clientdata(client);
 154
 155        /* Mark client detached */
 156        lm->i2c = NULL;
 157
 158        /* release sensor */
 159        wf_unregister_sensor(&lm->sens);
 160
 161        return 0;
 162}
 163
 164static const struct i2c_device_id wf_lm75_id[] = {
 165        { "MAC,lm75", 0 },
 166        { "MAC,ds1775", 1 },
 167        { }
 168};
 169MODULE_DEVICE_TABLE(i2c, wf_lm75_id);
 170
 171static const struct of_device_id wf_lm75_of_id[] = {
 172        { .compatible = "lm75", .data = (void *)0},
 173        { .compatible = "ds1775", .data = (void *)1 },
 174        { }
 175};
 176MODULE_DEVICE_TABLE(of, wf_lm75_of_id);
 177
 178static struct i2c_driver wf_lm75_driver = {
 179        .driver = {
 180                .name   = "wf_lm75",
 181                .of_match_table = wf_lm75_of_id,
 182        },
 183        .probe          = wf_lm75_probe,
 184        .remove         = wf_lm75_remove,
 185        .id_table       = wf_lm75_id,
 186};
 187
 188module_i2c_driver(wf_lm75_driver);
 189
 190MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 191MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
 192MODULE_LICENSE("GPL");
 193
 194